docs: Add RELEASING.md

RELEASING.md

@@ -0,0 +1,49 @@
+# Releasing
+
+**Release:**
+
+1. Ensure the repository is up to date and checkout the `develop` branch.
+
+2. [Update version](#version-update) and remove `-SNAPSHOT` suffix
+
+3. Update the `CHANGELOG.md`:
+   1. Replace `Unreleased` section with the release version
+   2. Add a link to the diff between the previous and the new version to the bottom of the changelog
+   3. Add a new empty `Unreleased` section on the top of the file
+
+4. Commit and push the changes.
+   ```bash
+   git commit -am "version: [version here]"
+   git push
+   ```
+
+5. [Create a Pull Request](https://github.com/RedMadRobot/gradle-infrastructure/compare/main...develop) from `develop` to `main` with the name of the next version.
+   Copy the changelog to the description.
+
+6. Merge the Pull Request and create a release tag on the `main` branch:
+   ```bash
+   # Pull main branch
+   git switch main
+   git pull --rebase origin
+
+   # Push the release tag
+   git tag [version]
+   git push origin [version]
+   ```
+   Release tag push triggers a release workflow on the CI which uploads release artifacts to Maven Central and creates a GitHub release.
+
+**After release:**
+
+1. Rename [milestone](https://github.com/RedMadRobot/gradle-infrastructure/milestones) "Next" to the released version and close it.
+2. Create a new milestone with the name "Next."
+3. In the `develop` branch [update version](#version-update) to the next potential version with suffix `-SNAPSHOT`.
+4. Commit and push.
+   ```bash
+   git commit -am "version: [version here]-SNAPSHOT"
+   git push
+   ```
+
+## Version Update
+
+1. Update a version in `gradle.properties` and `README.md`
+2. Update a version used in samples in `build.gradle.kts`